Liquid freezing apparatus



Oct. 20, 1970 A. J. Ross' LIQUID FREEZING APPARATUS Filed Nov. 12, 1968 2 Sheets-Sheet 1 Oct. 20, 1970 J, Ross 3,534,563

LlQU ID FREEZ ING APPARATUS Filed Nov. 12, 1968 2 SheetsSheet 2 United States Patent 3,534,563 LIQUID FREEZING APPARATUS Anthony J. Ross, 526 74th St., Holmes Beach, Fla. 33510 Filed Nov. 12, 1968, Ser. No. 774,913 Int. Cl. F25c 1/14 U.S. Cl. 62222 7 Claims ABSTRACT OF THE DISCLOSURE A liquid freezing apparatus having an internal evaporator disposed inside an annular freezing wall in which the evaporator has multiple refrigerant flow passages extending alongside each other and so arranged that refrigerant flows in relatively opposite directions therethrough with multiple accumulator chambers inside the evaporator to enable independent control of the flows of refrigerant through the several flow passages.

BACKGROUND OF THE INVENTION The invention relates to a liquid freezing apparatus having an internal evaporator disposed inside an annular freezing wall and in which the evaporator has multiple flow passages so arranged that refrigerant flows in relatively opposite directions through the several flow passages. The heat-absorbing capacity of the refrigerant flowing through an evaporator flow passages decreases as the refrigerant picks up heat during fiow from the inlet to the outlet end of the flow passage, and the evaporator is consequently somewhat colder adjacent the inlet end than adjacent the outlet end of the evaporator. In order to provide more uniform cooling of the evaporator, it has heretofore been proposed, as disclosed in the patent to A. J. Ross No. 3,143,865, dated Aug. 11, 1964, to provide dual refrigerant flow passages in the evaporator arranged so that the refrigerant flows in relatively opposite directions in the two flow passages. As disclosed in that patent, the flow of refrigerant to the two refrigerant flow passages was controlled by the same refrigerant expansion control, and the two refrigerant flow passages discharged into a common receiver or accumulator for return to a common refrigerant return line. While the multiple counterflow refrigerant flow passages in the evaporator did improve the uniformity of cooling of the evaporator, this prior apparatus did not have any provision for independently controlling the flows of refrigerant to the two separate evaporator fiow passages, and some problems were encountered in maintaining the proper rates of refrigerant fiow in each of the two evaporator flow passages.

SUMMARY OF THE INVENTION The invention is arranged to achieve more uniform cooling of an evaporator having multiple flow passages. The fiow of refrigerant to the several flow passages in the evaporator is separately controlled in a manner to maintain substantially the same condition of super-heat in the refrigerant returned from each of the several evaporator flow passages to the refrigerant producer. Multiple accumulators are provided for receiving the refrigerant from the several evaporator flow passages, and separate outlet conduits pass refrigerant from the several accumulators to the refrigeration producer return means while individual refrigerant flow control means are provided to individually control the flow of refrigerant to the inlets of the several evaporator flow passages. The refrigerant flow control means can advantageously be in the form of thermostatic expansion control valves arranged to control the flows of the refrigerant to the several evaporator flow passages in accordance with the refrigerant gas temperature in the respective outlet conduit.

3,534,563 Patented Oct. 20, 1970 The multiple flow passage evaporator is advantageously employed in a liquid freezing apparatus to not only achieve more uniform freezing of liquid over the evaporator surface but to also minimize fluctuations in the force required to separate the frozen liquid from the freezing wall caused by localized cold spots on the freezing wall. The multiple evaporator flow passages are located on the inside of an annular freezing wall, and the multiple accumulators are also located inside the annular freezing wall internally of the evaporator flow passages so that the refrigerating effect of the expanding refrigerant in the accumulators is also utilized in cooling the freezing wall. The multiple evaporator flow passages preferably extend in spiral fashion around the inside of the tubular freezing wall, and the multiple accumulators preferably extend lengthwise of the tubular freezing wall and crosswise of the multiple evaporator flow passages.

An important object of this invention is to provide a liquid freezing apparatus having an improved arrangement for controlling multiple flows of refrigerant through the evaporator to effect more uniform cooling of the evaporator.

A more particular object of this invention is to provide a liquid freezing apparatus in which the evaporator has multiple refrigerant flow passages arranged to extend alongside each other and pass refrigerant in relatively opposite directions therethrough, together with an improved arrangement for individually controlling the flows of refrigerant through the several refrigerant flow passages to substantially equalize the refrigerating effect of the several flow passages.

Yet another object of this invention is to provide a liquid freezing apparatus having an ice freezing surface on the outer side thereof and multiple refrigerant flow passages on the inner side and with multiple accumulators disposed inside the freezing wall.

These, together with other objects and advantages of this invention, will be more readily appreciated as the invention becomes better understood by reference to the following detailed description when taken in connection with the accompanying drawings, wherein:

FIG. 1 is a fragmentary vertical sectional view through a liquid freezing apparatus embodying the present invention and with parts of the refrigeration producer and liquid control apparatus shown diagrammatically;

FIG. 2 is an elevational view of the evaporator insert illustrating the refrigerant flow passages;

FIG. 3 is a fragmentary transverse sectional view through the evaporator taken on the plane 3-3 of FIG. 1;

FIG. 4 is a fragmentary vertical sectional view through a liquid freezing apparatus illustrating a modified refrigeration producer; and

FIG. 5 is a fragmentary vertical sectional view through a liquid freezing apparatus illustrating a further modified form of refrigeration producer.

In its preferred embodiment, the present invention is applied to a liquid freezing apparatus intended for use in producing a flake ice product. The liquid freezing apparatus is advantageously of the type disclosed in the aforementioned Pat. No. 3,143,865, and which includes a water jacket 10, an evaporator 11 immersed in the liquid storage chamber C formed by the water jacket, an ice removing device 12 which extends around the evaporator for removing frozen liquid therefrom, and a drive mechanism 13 for rotating the ice removi'ng device relative to the evaporator. The drive mechanism includes a drive motor 13:: and a speed reducing mechanism 131) having an output shaft coupled at 13d to the ice remover 12 to drive the same at a selected preferably low speed for example, 10 to 15 r.p.m. A liquid level control apparatus 14 is provided for controlling the flow of the liquid to be frozen to the liquid storage chamber and conveniently comprises a float reservoir 14a and a float control valve 14b in the reservoir for controlling the flow of liquid to be frozen from the liquid supply line 15 through a line 16 connected to the water jacket 10. The float valve is arranged to maintain the liquid level L in the chamber C at a level preferably adjacent the upper end of the freezing wall and below the ice discharge opening 17 in the water jacket. The ice removing device is rotatable relative to the freezing wall to remove frozen liquid therefrom and, in the embodiment shown, is in the form of a spiral rod of round cross section which extends around the evaporator and which defines an ice engaging surface 12a at the inner side of the spiral for engaging and removing the ice as it builds up on the evaporator. While the specific ice removing device illustrated constitutes 'a preferred form of ice remover, other forms of ice removing devices can be employed, if desired.

The evaporator 11 used in the liquid freezing apparatus comprises a freezing wall 25 which, in the embodiment shown, is of tubular configuration. The freezing wall is supported in fixed position as by attachment to a head 21 at its lower end, and the water jacket is conveniently detachably mounted on the head by fasteners 22 and sealed thereto by a gasket 23. The freezing wall may be sealed to the head in any suitable manner, as by braz ing, soldering, etc. A means is provided for forming at least two segregated refrigerant flow passages which extend alongside one another in heat-exchange relation with the freezing wall. In the form shown, two segregated refrigerant flow passages designated P and P are formed on the inside of the freezing wall 25 by a tubular insert 26 having ribs or grooves designated 1'; and r on its outer periphery and which engage the inside of the freezing wall 25 to form the passages P and P therebetween. It is to be understood, however, that the refrigerant flow passages could be formed in other ways, if desired, such as by using coiled tubular elements as disclosed in the aforementioned Ross patent.

The refrigerant flow passages P and P extend alongside each other and preferably extend in helical fashion along the freezing wall. In the present embodiment, each flow passage P and P makes only one pass lengthwise of the freezing wall and, for this purpose, the ribs r and r are formed with a double lead, it being understood that each refrigerant flow passage could make a second pass along the freezing wall, as disclosed in the afore mentioned Ross patent. The refrigerant flow passages have inlets and outlets adjacent opposite ends so arranged as to cause the refrigerant to flow in relatively opposite directions through the several flow passages. For this purpose, as best shown in FIG. 1, the flow passage P has an inlet X adjacent one end of the freezing wall and the flow passage P has an inlet X adjacent the other end of the freezing wall. Passages P and P have outlets Y and Y at the relatively opposite ends of the respective flow passage. Thus, refrigerant entering the inlet X at the lower end of passage P flows upwardly in spiral fashion around the inside of the freezing wall to the outlet Y adjacent the upper end of the freezing wall, and refrigerant entering the inlet X at the upper end of the flow pas-sage P flows downwardly in spiral fashion around the inside of the freezing Wall to the outlet Y adjacent the lower end of the freezing wall. The refrigerant thus flows in relatively opposite directions through the passages P and P and from relatively opposite ends of the evaporator. The ends of the tubular freezing wall are closed by plugs and, as shown, an upper plug or cap 28 is provided to close the upper end of the freezing wall, and a lower plug 29 closes the lower end of the freezing wall preferably at a level somewhat above the head 21. The upper and lower plugs 28 and 29 may be sealed to the freezing wall in any suitable manner as by brazing, soldering or the like. Refrigerant is supplied to the several refrigerant flow passages in the evaporator from a refrigerant producer means herein shown as a single compressor 31. As is conventional, the compressor has a low pressure refrigerant return line 33 and a high pressure refrigerant outlet line 34 connected to a condenser means 32. In this embodiment, the condenser means 32 is a single condenser common to both refrigerant flow passages. The high pressure refrigerant, after flowing through the condenser means, passes through the condenser outlet 35 to the evaporator.

Difiiculties have been encountered in maintaining balanced flows of refrigerant through the several evaporator flow passages, and an improved refrigerant control has been provided to independently control the flows of refrigerant through the several flow passages in a manner to maintain substantially equal refrigerating capacity in both flow passages. In accordance with the present invention, plural accumulator chambers designated A and A one for each of the evaporator flow passages P and P are provided and arranged to receive refrigerant from the outlets Y and Y of a respective one of the flow passages. The accumulator chambers are advantageously located inside the freezing wall -25 and internally of the flow passages P and P and are conveniently formed by providing a divider wall 41 inside the inner member 26 to extend crosswise thereof between the plugs 28 and 29 to divide the same into two segregated chambers. The outlets Y and Y of the flow passages are preferably arranged to discharge into the lower portions of the respective accumulator chambers to agitate the refrigerant in the lower portions of the accumulator chambers and prevent accumulation of oil therein. For this purpose, outlet Y communicates through a downwardly extending tube 45 with the lower portion of the accumulator chamber A and outlet Y communicates through a tube 46 with the lower portion of the accumulator chamber A First and second outlet conduits 47 and 48 respectively communicate with the accumulator chambers A and A at a point substantially above the bottoms thereof and preferably adjacent the upper ends thereof, and these outlet conduits extend out of the accumulator chambers through the plug 29. In the form shown in FIG. 1 in which the refrigerant producer is a single compressor, the outlet conduits 47 and 48 are interconnected externally of the accumulator chambers as through a fitting 39 with the low pressure return line 33. First and second inlet conduits 51 and 52 are respectively connected to the inlets X and X of the flow passages P and P and these inlet conduits extend out of the evaporator through the plug 29 and are connected to the outlet of the condenser means 32. When a single condenser is used, as shown in FIG. 1, the refrigerant flow from the outlet of the refrigerant producer 31 is divided or branched as by fitting 53 at the outlet of the condenser for connection to the separate inlet conduits 51 and 52 as shown in the drawings. Separate refrigerant flow control means are provided in the conduits 51 and 52 and, when using a single compressor which is common to the several evaporator flow passages, the refrigerant fiow control means are preferably in the form of separate thermostatic expansion valves 56 and 57, of conventional construction. The valves 56 and 57 are provided in the inlet lines 51 and 52, respectively, for independently controlling the fiows of refrigerant to the respective flow passages P and P and the thermal bulbs 56a,and 57a of the thermostatic valves 56 and 57, respectively, are mounted so as to respond to the refrigerant gas temperature in the outlet conduits 47 and 48 leading from the accumulator chambers A and A respectively. In order to avoid false response of the thermal bulbs to ambient temperature, the thermal bulbs are, of course, suitably insulated from the surrounding atmosphere by thermal insulation (not shown). The thermal bulbs are arranged to operate their respective thermostatic valves so as to maintain the same substantially constant condition of superheat in the refrigerant flowing through the several branch outlet conduits 47 and 48, the thermal bulbs being operative to close the respective thermostatic expansion valve as the temperature approaches a preselected lower value and to open the thermostatic expansion valve as the temperature rises above this preselected value. A resilient plug 29a may be provided in the head for sealing the inlet and outlet conduits to the plug 29 and to the head 21.

The embodiment of FIG. 4 is similar to that of FIG. 1 and like numerals are used to designate corresponding parts. In this embodiment, however, multiple condensers designated 32 and 32 are provided and their outlets 35 and 35 are individually connected to the separate refrigerant inlet lines 51 and 52 having the expansion controls 56 and 57 therein. The refrigerant producer outlet is branched at a fitting 53 ahead of the condenser 32 and connected to condensers 32 and 32". The condensers 32 and 32' respectively.

The embodiment of FIG. 5 is also similar to that shown in FIG. 1 and like numerals are used to designate corresponding parts. In this embodiment, the refrigerant producer comprises plural compressors designated 31 and 31" and condensers 32 and 32". The outlet conduits 47 and 48 from the separate accumulators are respectively connected to compressors 31 and 32" and the outlets 34 and 34" of the compressors 31 and 31" are respectively connected to codensers 32 and 32". The condensers 32 and 32" have their outlets 35 and 35" individually connected respectively to the inlet lines 51 and 52 having the refrigerant expansion controls 56 and 57 therein. When separate refrigerant compressors and condensers are used as shown in FIG. 5, the refrigerant expansion controls can be in the form of thermostatic expansion valves or, alternatively, can be in the form of capillary tubes, if desired.

From the above detailed description, the operation of the improved refrigerating apparatus is deemed clear. Briefly, the refrigeration producer delivers high pressure refrigerant to the inlet conduits 51 and 52, and the refrigerant flows through these conduits to the separate refrigerant flow passages in the evaporator are individually regulated by the refrigerant flow control means, 56 and 57 respectively. The refrigerant, after flowing through the evaporator flow passages P and P is discharged into the accumulator chambers A and A respectively, and then returned through the return conduits 47 and 48 to the refrigerant producer. The thermal bulbs 56a and 57a are disposed in heat exchange relation with the return lines 47 and 48 and operate the respective thermostatic expansion valves 56 and 57 to maintain the same substantially constant refrigerant gas temperature at the outlets of the flow passages, thus maintaining the same substantially constant condition of superheat in the refrigerant gas at the outlets of both evaporator flow passages.

Since the refrigerant flows in relatively opposite directions through the flow passages and from relatively opposite ends of the evaporator, the decrease in heat-absorbing capacity of the refrigerant in one evaporator flow passage, as it flows from the evaporator inlet to the outlet, is counteracted by the refrigerant flowing through the other evaporator flow passage. The individual refrigerant flow controls individually regulate the rate of flow of refrigerant in each evaporator flow passage so as to maintain substantially the same condition of superheat in the refrigerant at both outlet passages, thus balancing the refrigerating effect of both evaporator coils.

While the present invention has been described by reference to only a several preferred embodiments thereof, it will be apparent that numerous other modifications and embodiments may be devised by those skilled in the art, and it is intended by the appended claims to cover all modifications and embodiments which fall within the true spirit and scope of the present invention. Although two separate evaporator flow passages and accumulators have been specifically illustrated and described, more than two 6 evaporator flow passages and accumulators can be used, if desired.

What is claimed as new is:

1. In a device for freezing liquids including a drumshaped freezing wall, means for supplying liquid to the outer side of said freezing Wall, an ice removing device movable relative to said freezing wall for removing frozen liquid therefrom, means defining an evaporator at the inner side of said freezing wall, and a refrigeration producing means having a refrigerant supply means and a refrigerant return means for passing refrigerant through the evaporator, the improvement comprising;

said evaporator having means defining first and second segregated evaporator flow passages extending alongside each other at the inner side of said freezing wall 1n heat exchange relation therewith, said first and second evaporator flow passages each having an inlet and an outlet so arranged that refrigerant flowing from the inlet to the outlet in one flow passage passes 1n a direction relatively opposite to the direction of flow of refrigerant from the inlet to the outlet in the other flow passage,

means inside said drum-shaped freezing wall and internally of said evaporator flow passages defining first and second segregated accumulator chambers respectively communicating with the outlets of said first and second evaporator flow passages,

means including first and second refrigerant inlet condults communicating said refrigerant sup-ply means to the 1nlets of said first and second evaporator flow passages respectively to pass refrigerant from the refrigerant producing means to said first and second evaporator flow passages, and

means including first and second outlet conduits communicating said refrigerant return means with said first and second accumulator chambers respectively at a level substantially above the bottom thereof to pass expanded refrigerant from the accumulator chambers to the refrigerant return means,

said first and second inlet conduits respectively including first and second refrigerant flow control means for individually controlling the flow of refrigerant through said first and second evaporator flow passages.

2. A device for freezing liquids according to claim 1 wherein said first and second accumulator chambers extend lengthwise of said freezing wall in side-by-side relatron.

3. A device for freezing liquids according to claim 1 wherein said first and second flow passages extend in generally helical fashion along the inside of the freezing wall and said first and second accumulator chambers ex tend generally lengthwise of the freezing wall inside the first and second flow passages.

4. A device for freezing liquids according to claim 1 wherein said inlets of said first and second flow passages are located adjacent relatively opposite ends of the freezing wall and the outlet of each flow passage is located adjacent the end of the freezing wall remote from the respective inlet.

5. A device for freezing liquids according to claim 3 wherein said accumulator chambers extend generally lengthwise said freezing wall, said first and second inlet conduits and said first and second outlet conduits each extending out from one end of the drum-shaped freezing wall.

6. An apparatus according to claim 1 wherein said first and second refrigerant flow control means include first and second thermostatic expansion valves in said first and second refrigerant inlet conduits, said first and second refrigerant expansion valves having first and second thermal bulbs respectively associated with said first and second outlet conduits to control the flow of refrigerant to said first and second flow Pas to maintain approximately the same refrigerant gas temperature at the several outlet conduits.

7. In a device for freezing liquids including a drumshaped freezing wall, means for supplying liquid to the outer side of said freezing wall, an ice removing device movable relative to said freezing wall for removing frozen liquid therefrom, means defining an evaporator at the inner side of said freezing wall, and a refrigeration producing apparatus having a refrigerant supply line and a refrigerant return line for passing refrigerant through the evaporator, an improved evaporator branch circuit for elfecting substantially uniform cooling of the freezing wall comprising;

said evaporator having means defining first and second segregated refrigerant flow passages extending alongside each other at the inner side of said freezing wall in heat exchange relation therewith, said first and second flow passages each having an inlet and an outlet so arranged that refrigerant flowing from the inlet to the outlet in one flow passage passes in a direction relatively opposite to the direction of flow of refrigerant from the inlet to the outlet in the other flow passage,

means inside said drum-shaped freezing wall defining first and second segregated accumulator chambers respectively communicating with the outlets of said first and second flow passages,

first and second thermostatic expansion values each connected to said high pressure supply line and respectively connected through first and second inlet branch conduits to the inlets of said first and second flow passages to control the flow of refrigerant thereto,

first and second branch outlet conduits respectively communicating said refrigerant return line with each said first and second accumulator chambers at a level substantially above the bottom thereof to pass expanded refrigerant from both accumulator chambers to the return line;

said first and second thermostatic expansion valves having first and second thermal bulbs respectively associated with said first and second branch outlet conduits to control the flow of refrigerant to said first and second flow passages to maintain approximately the same refrigerant gas temperature in the several branch outlet conduits.

References Cited UNITED STATES PATENTS 3,143,865 8/1964 Ross 62-354 WILLIAM E. WAYNER, Primary Examiner US. Cl. X.R. 62354, 503 

